Traditional circuit board assemblies use rigid insulated materials to form a substrate for the mounting of electronic components. According to well known prior art designs, the signal flow between electronic components is effected by wire connections (e.g. copper traces) printed on the substrate. The electronic components themselves are connected to these wire traces via solder. The rigidity of the substrate material prevents cracking of the copper solder joint connections and insures the integrity of these connections when the device is subjected to mechanical stress.
Certain specialized applications require circuit board assemblies of size greater than approximately 4 cm.sup.2 to be flexible. One such application is mail efficiency processing measurement wherein the circuit board assemblies are disposed within or on envelopes which pass through mail sorting equipment. The circuit board assemblies in such an application may be designed to incorporate low frequency antennae and associated electronic circuitry. The circuit board assembly must be designed to withstand the stresses of being passed through mechanical sorting machines.